Model train sets typically include an electrically driven model train engine which receives power from a voltage applied to the tracks and picked up by the train""s electric motor. A transformer is typically used to apply the power to the tracks. The transformer is used to control the amplitude and polarity of the voltage, which in turn controls the speed and direction of the model train. In 2-rail O gauge, HO and N gauge systems, the voltage is a DC voltage. In 3-rail O gauge LIONEL systems, the voltage is an AC voltage, i.e., the 60 Hz line voltage available from a standard wall socket, stepped down by the transformer to not more than 24 volts.
Model train enthusiasts also have a desire to control other features of the train besides speed and direction. For example, users may wish to control the blowing of a whistle. To control the whistle LIONEL trains impose a DC voltage on top of the AC line voltage, which the electric engine then detects. One limitation to this method is in the number of controls that can be transmitted, since there are only plus and minus DC levels available, along with varying amplitudes.
LIONEL trains originally used a mechanical lever on the engine to reverse the direction of the model train because AC electric motors do not change direction with voltage polarity reversal as applied to the track. LIONEL subsequently introduced the E-Unit which allowed a certain degree of remote control over the direction of the train. The E-Unit is typically mounted on the engine and has a solenoid coil that is powered from the track. Upon the momentary removal of power from the track, the solenoid coil releases and the solenoid plunger dislodges a pawl or pivoting arm away from a ratchet tooth of a drum. When power is restored to the solenoid, the plunger is withdrawn upward until the pawl catches the tooth on the drum rotating it to the next state. The drum has spring contacts which connect to the track power and the electric motor. The contacts switch as the drum is rotated to change the connections of the motor armature with respect to the motor field. The rotating drum sequences the electric motor through the following states: forward, neutral before reverse, reverse, and neutral before forward.
Although a monumental improvement, the E-Unit suffered from the disadvantage that it controlled the model train by removing power. Dirty tracks and loose connections can unintentionally cause unwanted power interruptions. In turn, these interruptions can cause the E-Unit to change its state without being requested to do so by the user. Another disadvantage to the E-Unit was that it required the solenoid to be on continuously when power is applied to the track. This causes in a continuous buzzing by the E-Unit during operation which also was a waste of power. The buzzing noise is caused by the AC field of the electric motor vibrating the plunger as the polarity of the AC field alternates.
To solve the problems associated with the E-Unit a control system with a modified E-Unit was developed. The modified control system operates by sending control signals to the model train itself, rather than by interrupting power to the train track. One disadvantage to this system was that a model train designed for the modified control system will not operate on old train tracks which control the model train through momentary power interruptions.
To improve on the modified control system, a control circuit was developed that would momentarily apply power to an E-Unit solenoid upon detecting a momentary power interruption. After the E-Unit drum advances, power is removed from the solenoid allowing the plunger to drop and dislodge the pawl. This position represents the rest state of the E-Unit. In the rest state power is removed from the E-Unit eliminating any noise. The E-Unit is then ready for movement into the next state. The dislodging of the pawl is the first half of the rotation operation which is done ahead of time. The first half of the rotation nonetheless does not change the contact position. The contact position then occurs when power is reapplied causing the plunger to be drawn up causing the drum to rotate.
This prior art model train control system is known as the TRAINMASTER(copyright) Control System (TCC) which is sold by LIONEL. The TrainMaster Control System sold by LIONEL is disclosed in U.S. Pat. Nos. 5,251,856 and 5,441,223 to Young et al., both hereby incorporated in this written description by reference. The TCC also provides a remote control device used to transmit signals to a base unit connected between the transformer and the train track. The base unit then transmits signals to particular engines using a digital address imposed upon the track power signal. The TCC remote control device uses frequency shift keying (FSK) modulation to transmit information from the transmitter to the model train engines. Each model train engine is equipped with a receiver having a particular digital address. The information received by the model train engine controls the operation of the train including its direction. One of the benefits to the LIONEL TCC is that it can be used to override the model train""s connection to the modified E-Unit. This allows remote control to be used independent of track power and backward compatibility for model train sets that use track power interruptions to control standard E-Units.
Today, one of the biggest draw backs to the LIONEL TCC system is that there is no way to add TCC to an existing model train not already properly equipped by LIONEL. There have been no aftermarket products available which would allow the addition of the LIONEL TRAINMASTER Command Control to existing model trains. Because of this lack of aftermarket conversion products many model trains become useless on a TCC train track. Many train enthusiasts have invested significant amounts of money in older, non TCC model trains and therefore are hesitant to switch to the TCC system despite its superior performance and characteristics.
Therefore, in light of the foregoing deficiencies in the prior art, the applicant""s invention is herein presented.
The present invention provides a model train sound board interface for making model trains compatible with the LIONEL TRAINMASTER Command Control (hereinafter referred to as xe2x80x9cCommand Controlxe2x80x9d) system. The model train sound board interface of the present invention, also referred to as a Universal Command Upgrade Board (hereinafter referred to as xe2x80x9cUCUBxe2x80x9d), can be retrofit in model trains in order to upgrade all 3-rail model train engines for use with Command Control.
In one embodiment of the present invention, the model train sound board interface is comprised of circuitry which interprets serial digital data received from the LIONEL TRAINMASTER Command Control transmitter to determine what command the user is sending to the model train engine. Once the command is interpreted the circuitry provides the appropriate output signal to carry out the command. The circuitry of the preferred embodiment includes a microprocessor for interpreting serial data from the LIONEL TRAINMASTER Receiver, purchased separately from Lionel and known in the industry as the xe2x80x9cR2LCxe2x80x9d. The R2LC receiver is connected to the microprocessor through a standard connector included with the model train interface.
Also included in the preferred embodiment are negative 5 and approximately negative 9 volt power supplies for providing consistent and filtered power to some external sound boards, an H-bridge triac motor driver optically coupled to digital output ports on the R2LC receiver and DC offset circuitry comprised of variable voltage regulators again optically coupled to the UCUB microcontroller. While the model train sound board interface can be configured to control just about any function of the model train, in the preferred embodiment the interface is configured to provide control of speed, direction and sound effects. In particular, the DC offset circuitry provides positive and negative DC offsets required by many popular aftermarket sound boards for model trains which provide life-like sound effects.
These along with other objects and advantages of the present invention will become more readily apparent from a reading of the detailed description taken in conjunction with the drawings and the claims.